1. Field of the Invention
This invention relates to a fire-extinguishing device for an oil burner, and more particularly to a fire-extinguishing device of the type that an air chamber is arranged outside a wick receiving chamber through which the wick receiving chamber is selectively communicated with an ambient atmosphere.
2. Description of the Prior Art
A fire-extinguishing device of such a type as described above is classified into two types. One type is that air is introduced from an air chamber to a wick receiving chamber at the time of fire-extinguishing. The device tends to discharge bad odor to a room during fire-extinguishing, accordingly, it is constructed to open, only in an emergency such as earthquake, a through-hole via which the air chamber is communicated with an ambient atmosphere. The other type is that introduction of air from an ambient atmosphere through an air chamber and a wick receiving chamber to a combustion section is stopped by closing a through-hole of an air chamber for communicating the air chamber to an ambient with a valve at the time of fire-extinguishing.
The assignee proposed a fire-extinguishing device for an oil burner which accomplishes rapid fire-extinguishing by only operation of lowering a wick through a wick operating shaft and put it into practice. The device is typically disclosed in U.S. Pat. No. 4,363,620 issued on Dec. 14, 1982 and Japanese patent publication No. 25962/1986 corresponding thereto, the disclosure of which is incorporated by reference. In the fire-extinguishing device disclosed, a wick receiving chamber is formed into a width larger than a thickness of a wick received therein so as to allow air to pass through the wick receiving chamber. Also, an air chamber is so arranged that it may be communicated to the wick receiving chamber through an opening defined between both chambers. The air chamber is provided with a through-hole via which it is communicated directly to an ambient atmosphere and which is opened or closed by a valve, so that air may be fed from an ambient atmosphere through the air chamber and wick receiving chamber to a combustion section of an oil burner during combustion operation of the oil burner. Such construction permits the air chamber to be filled with fresh air during combustion operation. In fire-extinguishing operation, the through-hole of the air chamber is closed with the valve and the wick is lowered to a level below the opening between the wick receiving chamber and the air chamber, resulting in a flame being drawn into the wick receiving chamber. The flame then consumes air in the closed air chamber to reduce pressure of the air chamber and fuel oil gas vaporized from the lowered wick is then diffused into the air chamber of reduced pressure, to thereby lead to fire-extinguishing. Thus, it will be noted that the fire-extinguishing device proposed significantly prevents discharge of bad odor to a room because of preventing fuel oil gas generated during fire-extinguishing operation from being diffused to the room.
In the conventional fire-extinguishing device described above, the valve is adapted to keep the throughhole of the air chamber open during combustion operation of the oil burner and the opened through-hole is exposed directly to an ambient atmosphere. Accordingly, the fire-extinguishing device often causes an excessive amount of air to be introduced via the through-hole into the combustion section to deteriorate combustion characteristics of the oil burner, particularly when wind blows against the oil burner.
Also, misuse of gasoline of high volatility as compared with kerosene has much possibility of causing vapor of gasoline to leak from an oil reservoir of an oil burner through an opening or through-hole of the oil reservoir to a room to lead to a fire. Unfortunately, the conventional fire-extinguishing device fails to take any step to avoid such a danger.
Also, in the conventional fire-extinguishing device described above, a valve actuating mechanism for actuating the valve for operating the through-hole of the air chamber is complicated in its structure and troublesome in assembling. Also, the prior art fails to provide a valve structure which is successfully applied to the fire-extinguishing devices of both types described above.